Radioactive Decay

Nuclides exist in two main forms, stable and unstable. A nuclide is considered to be stable if there is no proof of its spontaneous transformation into another nuclide. The probability of transformation is characterized by the half-life, which is defined as the time needed for half of the starting amount of an unstable nuclide to transform. Elements above lead are all unstable and have very long half-lives (order of 10⁸–10¹⁰ years) compared to the age of the atom (assumed to be formed some 10 billion years ago).

It can be thought that radium could become very dangerous in criminal hands, and here the question can be raised whether mankind benefits from knowing the secrets of Nature, whether it is ready to profit from it or whether this knowledge will not be harmful for it.

The example of the discoveries of Nobel is characteristic, as powerful explosives have enabled man to do wonderful work. They are also a terrible means of destruction in the hands of great criminals who are leading the people towards war. I am one of those who believe with Nobel that mankind will drive more good than harm from new discoveries. Pierre Curie (1859–1906), 1903 Nobel Prize address.